Method of milling woolcontaining fabrics



Feb. 27, 1968 J. H. SIEBER 3,370,330

METHOD OF MILLING WOOL-CONTAINING FABRICS Original Filed May a, 19 63 2 sheetssheet 1 filling Uni? Reseryoir Fig.1

Johannes H. Sieber I1\'VE;\'"IOR Feb. 27, 1968 J. H. SIEBER 3,370,330

METHOD OF MILLING WOOL-CONTAINING FABRICS Original Filed May 8, 1963 2 Sheets-Sheet 9 Fig.3

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. Johannes H. Sieber 'E.\"T0R.

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United States Patent 3,370,330 METHOD OF MILLING WOOL- CONTAINING FABRICS Johannes Helmut Sieber, Neuass, near Augsburg, Germany, assignor to Firma Bohler & Weber KG., Augsburg, Germany, a corporation of Germany Application May 8, 1963, Ser. No. 278,955, now Patent No. 3,330,015, dated July 11, 1967, which is a continuation-in-part of application Ser. No. 160,640, Dec. 19, 1961. Divided and this application May 3, 1965, Ser. No. 461,224 Claims priority, application Germany, Dec. 23, 1960, B 60,633 5 Claims. (Cl. 2619) This application is a division of my copending application Serl No. 278,955, filed May 8, 1963, as a continuation-in-part of my then pending application Ser. No. 160,640 filed December 19, '1961, now abandoned.

My present invention relates to the milling of fabric. In application Ser. No. 160,640 I disclose a process for the milling and after-treatment of fabrics with water wherein the water is transferred onto the fabric from a liquid vehicle, containing a dry-cleaning solvent, in which the water formed a dispersion. This technique has been found to have general applicability in the shrinkage of nonwool fabrics as well as those containing wool, for the impregnation of fabrics with various treating agents and other fabric-finishing steps in addition to the milling or fulling mentioned above.

Generally speaking, treatment of fabrics with water has been carried out heretofore by immersion and agitating the fabric in a water bath. This method, by virtue of the fact that an excess of water is always present in contact with the fabric, is complicated by a number of variables, all of which must be controlled for effective milling. In the direct water treatment of fabric, for example, temperature is of prime importance since wool, cotton, viscose rayon and like fabrics swell more rapidly with increasing temperatures. The shrinkage effect is also more significant in hot water than in cold water. When wool fabrics are involved, felting occurs very rapidly in the presence of pure water so that extremely close control over the treatment time is essential. Additionally, in a pure aqueous medium, control over pH must be observed if reproducibility is to be insured. As a consequence of the aforementioned complication arising from the aqueous milling of fabrics, the industry has long sought to control the several variables in a convenient manner and to eliminate as variables as many factors as possible. Efforts to eliminate controllable and uncontrollable variables in the treatment of fabrics in general have led to only limited success heretofore. It may, for example, be noticed that the impregnation of fabrics with water-soluble material in the presence of a purely aqueous medium has shown that considerable care must be taken with respect to the same variables which governed milling action.

It is an object of the present invention to provide an improved method of milling wool-containing fabrics.

Another object of this invention is to extend the principle advanced in my above-identified copending application to the controlled treating of fabrics in general.

Still another object of this invention is to provide an improved method of treating fabrics with Water-soluble treatment agents.

A further object of my invention is to provide a process for controlledly shrinking fabrics.

Yet another object of this invention is to provide an improved apparatus for treating fabrics and milling Woolcontaining textiles.

These objects and others, which will become more readily apparent hereinafter, are attained, in accordance with "ice the present invention, by a method of treating fabrics wherein water is dispersed in a liquid vehicle in which it is only slightly soluble but in the presence of a quantity of a surface-active agent sufficient to stabilize the water dispersion but less than that required to solubilize the water. The fabric is then immersed in the liquid vehicle and absorbs water therefrom while being agitated therein, e.g. by tumbling.

I have discovered that, under these circumstances, water completely saturates the liquid vehicle or solvent so that the latter can always be considered to possess a humidity of at the operating temperature. Since the amount of water which will saturate the solvent is well defined, no difficulties arise from excess moisture or insuflicient moisture. The liquid vehicle is preferably composed entirely of a dry-cleaning solvent of conventional type since such solvents are readily removed from the fabric and have a water-saturation point wherein the water content is not insignificant but yet below the level at which undesirable etfects will result. As the fabric absorbs moisture from the solvent, additional water in a dispersed state, but not yet in solution, dissolves to maintain saturation Of the solvent. As previously pointed out, the surfaceactive agent is present in suflicient quantity to stabilize the water dispersion but not in a quantity capable of solubilizing it within micelles of the surfactant.

I am aware that earlier efforts in the dry-cleaning industryhave involved the use of surface-active agents to stabilize and increase the quantity of water dispersed within a dry-cleaning solvent. It must be noted, however, that these efforts were based upon an entirely different principle of operation from that involved in the present invention. It is an essential aspect of such dry-cleaning processes that water be provided in the solvent to remove water-soluble soils, the water being provided in a substantial proportion of the dry-cleaning solvent. To insure that the soils dissolved by the water were removed and prevented from again depositing upon the fabrics, sufficient quantities of a surface-active agent were provided to solubilize the water in micelles. In such methods the quantity of surface-active agent was invariably greater than the quantity of water to insure total solubilization and, in fact, was often ten to twenty times greater than the quantity of water it was desired to solubilize. In contradistinction, the present invention derives from the discovery that water can be dispersed in a dry-cleaning solvent in the presence of a quantity of surface-active agent less than that of water and suflicient only to stabilize the dispersion but incapable of solubilizing the water so that dispersed water is free to go into solution in the solvent without dissolving in the surface-active agent. In dry-cleaning systems operating with the aid of water, moisture solubilizedin surfactant micelles is prevented from freely dissolving in the organic solvent as required.

According to a further feature of the present invention, the liquid vehicle, consisting predominantly of the drycleaning solvent, is circulated through the fabric and the water dispersed therein replenished duringthis circulation. I have discovered that excellent results are obtained when the dry-cleaning machine or immersion receptacle in which the treatment of the fabric is carried out is provided with a solvent-circulating system including pump means capable of effecting a fine dispersion of the water in the solvent and supply means for the water and/or the surface-active agent is disposed rearwardly of the pump in the direction of circulation of the liquid. Advantageously, the system can be provided with means for extracting the liquid vehicle from the fabric at the conclusion of the treatment process, control means being provided to direct a portion of the solvent removed from the treatment vessel to a distilling means for purification.

' taining fabrics.

Preferably, the free liquid within the receptable is first drained into a storage tank or reservoir with only-the tailings, removed by extraction, being fed to the distilling device.

As previously indicated, the quantity of surface activation may be equal to a small fraction of that of the dispersed water (between 0.1 and 10% by Weight of the fabric to be treated), the water being present in an amount ranging between substantially and 50% by weight of the fabric. Best results are obtained when the liquor ratio, i.e. the ratio of fabric in kilograms to total liquid vehicle in liters, ranges between 1:2 to 1:50 and preferably is about 1:10. The relative quantities of Water dispersed in the dry-cleaning solvent and surface-active agent are more dramatically demonstrated by noting that the preferred range of surfactant quantities lies between 0.5 and 3% by weight of the fabric while'the water quantity is between 5 and 20% by weight of the fabric.

Almost any dry-cleaning solvent is suitable for carrying out the process of the present invention, it being noted that solvents in which water is only slightly soluble are the most satisfactory. The most practical solvents for use in treating fabrics in the manner described above are the chlorinated hydrocarbons and solvent mixtures containing aliphatic, aromatic and alicyclic hydrocarbons of the Stoddard type. Solvents having particular suitability are those described in ASTM Standards D48452 and hereafter designated as Stoddard solvents. Of the chlorinated hydrocarbons, perchlorethylene and trichlorethylene are most suitable since they are readily removed from the fabric at the conclusion of treatment by conventional means.

According to another aspect of the present invention, the water dissolved in the dry-cleaning solvent serves as a carrier for water-soluble adjuvants for treating the fabric. In this case the adjuvant, which can be a syntheticresin stiffening agent, a softening medium or any other water-soluble substance with which it is desired to treat the fabric, is added to the solvent subsequently to the dispersion of the water and surfactant therein or concurrently with such dispersion. The adjuvant is found to dissolve in the dispersed water and to be carried with it onto the fabric as the dispersed water itself dissolves-in the solvent'upon 'withdrawal of water therefrom by the hydrophilic fabric.

Still another feature of the present invention resides in the treatment of both wool and other fabrics by this technique for controlledly shrinking them to the desired dimensions. Whereas the present technique is particularly suitable for milling and felting wool-containing fabrics, it should be notedthat treatment of fabrics with water is more generally applicable. Thus, cotton fabrics may be treated, according to the invention, with water in a solvent vehicle as described above to shrink the fabric in a controlled manner with time and temperature being the sole variables determining the quantity of water absorbed by the cotton fabric. In this connection it may be pointed out that direct immersion of cotton fabrics in water often results in an uncontrolled shrinkage since many other factors enter into the determination of the quantity of water absorbed by the fabric and affecting shrinkage thereof. Again adjuvants may be carried by the Water to the cotton fabric in order to treat the latter.

The surface-active agents employed in the present method include anionic, cationic and nonionic types as well as conventional soaps. It is desirable, for themost part, to operate at about room temperature when milling and fabric shrinkage are to be carried out, but at higher temperatures (say 30-40 C.) when felting is required. It may be noted that the organic solvents to be used have a water saturation level on theo rder of 0.04% by weight at 25 C., a preferred temperature for milling wool-con- The above and other objects, features and advantages of the present invention will become more readily apparent from the following description and examples, reference being made to the appended drawing in which:

FIG. 1 is an axial cross-sectional view through a drycleaning machine of the rotating-basket type, schematically showing a system embodying the present invention;

FIG. 2 is a graph of the sequence of operation of the valves and other control elements of the system of FIG. 1;

and

FIG. 3 is a diagram illustrating another apparatus for carrying out thepresent method. a

In FIG. 1, I show a dry-cleaning machine 10, of a generally conventional type, wherein a receptacle 11 encloses a rotating fabric-receiving basket 12 into which the fabric 13 can be introduced via an opening 14 in the receptacle which can be closed by a door 15. The perforated basket 12 is provided with vanes 16 for agitating the fabric in the liquid 17 contained by the receptacle. The basket 12 is provided with a driven pulley 18 connected via a belt 19 with the drive wheel 20 of a motor M whose two-speed transmission 22 is normally in its low-speed state. As electromagnetically operable clutch C is provided on the transmission for shifting it to its high speed. The motor M also carries a pump for draining solvent from the receptacle 11.

A reservoir 24 is disposed above receptacle 11 and is connected thereto by a pipe 25 in which is positioned an electrically operable valve V for controlling the addition of solvent to the receptacle 11. A distilling unit D, positioned above the reservoir24, is connected thereto by another pipe 26 whereby regenerated solvent can be drained into the reservoir 24 by gravity. A conduit 27 leadsfrom the outlet of the pump and supplies a first duct means 28 via an electrically operable valve V to convey the liquid vehicle to the distilling unit D. A second duct means 29,

having an electrically operable valve V is also provided to convey the liquid directly to the reservoir 24. A conduit means 30 with its valve V forms with line 27 and pipe 25 a closed system for circulating the solvent, as will be described hereinafter.

The intake end of pump 23 is fed by a drain pipe 31 from the receptacle 11 and serves as the termination for a supply line 32 whose gravity-fed dispenser 33 adds water and surfactant to the solvent. The amount of water added can be determined by a manually adjustable valve 34, although sensing means 35, responsive to the water content of the solvent, may be provided in line 27 for automatic control of this valve. A two-position cutoff valve V is provided in supply line 32 for initiating and halting flow of water into the solvent.

A filter F, whose inlet 36 is connected to line 27 via an electromagnetically operable valve V can also be provided to remove solid and certain liquid impurities from the solvent stream as desired. The outlet pipe 37 of filter F contains a check valve 38 to prevent backflow of the liquid. An air-inlet duct 39, supplied by a blower, not shown, is fitted with an electrically controlled valve V for supplying a blast of drying air to the receptacle 11. An outlet duct 40 is designed to carry air saturated with the solvent to the distilling unit D for recovery of the solvent. A timer and programming means 41, which can be of the card-control type, is provided for sequentially operating the valves. Such programmers are well known per se and need not be described in detail.

The operation of the apparatus of FIG. 1 willnow be described with reference to a five-minute milling operation. The programming sequence may, of course, be altered as desired to suit any particular requirements. The fabric, e.g. wool-containing garments to be milled, is introduced into the basket 12 via opening 14 and the door 15 then closed. The programmer is then turned on to operate motor M which functions during the entire cycle (FIG. 2). The programmer also energizes valve V to permit solvent to drain from the reservoir 24 into the receptacle 11. The quantity of solvent thus added may be controlled by suitable float means well known in the art and not shown herein. After approximately three-quarters of a minute (FIG. 2), a period sufiicient to permit introduction of the desired quantity of solvent, valve. V is closed and valve V opened. Valve V has meanwhile been energized so that the pump 23 circulates the drycleaning solvent from and backto the receptacle 11. This pump is preferably of the centrifugal type to ensure thorough agitation of the solvent. Concurrently with or shortly after the actuation of valve V valve V is opened to admit water and surfactant from the supply means 33 into the solvent stream rearwardly of the pump 23 in the direction of circulation of the liquid. The pump thus constitutes a dispersing means which forms a fine dispersion of water in the solvent. The water, carried by the solvent, is thus brought into contact with the fabric 13 as the drum rotates at low speed for the duration of the milling operation shown to be approximately 4 minutes.

At the five-minute point, ,valves V and V; are closed while valve V remains open and either valve V or V is opened. The pump then displaces the free solvent of receptacle 11 into reservoir 24 directly orinto the latter via the filter F. Solvent trapped in the fabric 13 is not, however, drained from the receptacle 11 at this time. After approximately one minute of draining, valve V or V is closed and valve V opened concurrently with energization of clutch C and the distilling unit D. This energization of clutch C shifts the transmission 22 into its high speed whereupon the basket 12 is rotated rapidly to force liquid out of the fabric 13 by centrifugal force. This liquid constitutes the tailings and is conveyed by pump 23 to the distilling unit D via line 28 whose valve V-, has been opened as previously noted. When the extraction stage has been completed, clutch C is tie-energized and valve V closed and the basket 12 rotated again at low speed to tumble the fabric 13. The valve V is then 0perated to admit a stream of drying air, heated if desired, to the receptacle 11. As the fabric dries, the solvent-containing gas is carried to the distilling unit D wherein the solvent is recovered. At the conclusion of the operating cycle, motor M is cut off and the fabric removed.

In FIG. 3 I show an arrangement wherein a fabric 42 can be continuously treated. The fabric can be drawn from a supply roll 43 or from earlier processing apparatus and passes into a receptacle 44 containing the solvent 45 in which water and a surface-active agent are dispersed. An outlet tube 46 conveys a solvent to a pump 47 which circulates it back to the receptacle 44. A dispenser 48 is provided to feed water and surfactant to the conduit means 36 etc. rearwardly of pump 47 but forwardly of the receptacle 44. A wheel 49, with radially extending arms 50, serves to agitate and maintain the fabric 42 below the level of the liquid 45 for a period sufficient to carry out the desired treatment, From the receptacle 44 the fabric can pass in a drying zone 51 wherein blowers 52, diagrammatically shown, remove the solvent which can be recovered and returned to the tank. A distilling unit or reservoir may be provided as shown in FIG. 1.

EXAMPLE I In a dry-cleaning machine of the aforedescribed type (FIG. 1), I dispose 4 kg. of a wool-containing knitwear, consisting substantially of 70% wool and 30% viscose rayon. The knitwear is in a damp state and contains 11.5%, by weight, of water. The drycleaning machine is charged with a perchlorethylene cleaning solvent at a liquor ratio of 1:10 (for one kilogram of goods ten liters of solvent). A quantity of a surface-active agent equal to 1% of the weight of the fabrics is distributed in the sol vent. It should be noted that the water/surfactant weight ratio is approximately 11.5 :1. An anionic emulsifier (sodium dodecylbenzinesulfonate) serves as the stabilizer for the dispersion. The milling time is approximately 15 minutes. The dried knitwear is found to have been milled to the desired extent without undue felting.

6 EXAMPLE II A woven fabric containing approximately 70% wool is treated in the dry-cleaning machine with Stoddard solvent (ASTM D48452) at a liquor ratio of 1:5 (for one kilogram of fabric five liters of solvent). Approximately 14 kg. of fabric are treated. A paste soap (560 cc.) containing 75 g. of water is then added. In this case itis desirable that a total water content of 17%, based upon the weight of the fabric, be employed. Approximately 2.3 kg. of water must then be added to the drycleaning solvent together with or subsequent to the addition of the soap at the supply means whereupon the water is dispersed thoroughly in the solvent by the pump. The fabric is milled for 15 minutes whereupon the solvent is drained to the reservoir, and is then extracted for 3 minutes, the liquid tailings being conducted to the distilling unit. Again the dried fabric shows the desired milling effect.

EXAMPLE III 18 kg. of woolen blankets, consisting of 30% by weight cotton and 70% by weight wool, just off the loom and still containing size and natural oils, are treated for 5 minutes in 360 liters of trichlorethylene dry-cleaning solvent (liquor ratio 1:20). The blankets are then extracted, with the solvent distilled and returned to the receptacle by way of the pump which disperses 360 g. of a nonionic emulsifier (a nonylphenylethyleneoxide condensate such as the one marketed under the trademark Tergitol NPX) together with 2.2 liters of water (approximately 12% calculated on the weight of the blankets) in the recirculating solvent stream. After milling of the fabric in this solution for 5 minutes, the spent liquor is returned to the reservoir with the tailings being passed through the distilling unit. After drying for 20 minutes at C., the blankets are found to be not only clean but also free of size and provided with the desired milling effect so that only a final napping treatment is necessary to finish the fabric.

EXAMPLE IV A wool cardigan is milled in a perchlorethylene solvent (liquor ratio 1:10) in the presence of 12% water based upon the weight of the fabric. About 1% by' weight of the fabric of a quaternary ammonium compound (as a cationic surface-active agent) stabilizes the water-in-solvent emulsion. The quaternary ammonium compound is a commercially available substance such as that marketed by Armour & Co. under the trade name Arquad HT and containing long-chain alkyl groups. A milling time of approximately 12 minutes is used. If it is desired to apply a filler or softener to the fabric, this adjuvant can be dissolved in the vehicle for transfer to the fabric by the water dispersed therein. For example, approximately 0.8% by weight of the fabric of dextrin can be dissolved in the system just described for the treatment of a woven fabric consisting of 30% viscose rayon and 70% wool. Substantially all of the dextrin dissolved in the vehicle is deposited in the fabric and adsorbed thereby.

EXAMPLE V A l00%-woo1 material is felted in the dry-cleaning machine or receptacle of FIGS. 1 or 3 with a perchlorethylene liquor ratio of 8: 1. The solvent containing 40% water, based upon the weight of the fabric, and the aforedescribed nonionic emulsifier is used. The treatment temperature is 40 C. A stiffening adjuvant (10% by weight of the fabric of polyvinyl alcohol) is added to the vehicle for transfer to the felt by the dispersed water. After at least partial drying the felt can be blocked and set.

EXAMPLE VI A cotton-knit fabric is agitated for 5 minutes in perchlorethylene (liquor ratio 1:10) in the presence of a softening-type surface-active agent. Approximately 1% of the weight of the fabric of the sulfated diisobutylamide of oleic acid marketed under the trademark Humectol is used as the surfactant and serves to stabilize an emulsion of 35% water, by weightof the fabric, in the solvent. The fabric shrinks by about 6% to the desired dimensions.

I claim:

1. A method of milling a wool-containing fabric, comprising the steps of dispersing water in an organic vehicle containing a dry-cleaning solvent and present in a quantity sufiicient to provide a liquor ratio from substantially 1:2 to 1:50 based upon the weight of said fabric to be treated, said water being dispersed in the presence of a quantity of a surface-active agent equal to a small fraction of that of the dispersed water and sufficient to stabilize the water dispersion but less than that required to solubilize said water, said quantity of surface-active agent ranging between substantially 0.1% and of the weight of said fabric;

immersing said fabric in said vehicle while agitating said fabric therein for a period of time compatible with the fabric treated and at a temperature of said vehicle of about C. suflicient to result in substantial absorption of water from said vehicle by said fabric but less than that at which said fabric becomes felted;

removing the fabric from said vehicle; and thereafter drying said fabric.

2. A method of milling a wool-containing fabric, comprising the steps of: a

(a) dispersing water in an organic vehicle containing a dry-cleaning solvent present in a quantity sufiicient to provide a liquor ratio from substantially 1:2 to 1:50 based upon the weight of said fabric to be treated, said water being dispersed in the presence of a quantity of a surface-active agent equal to a small fraction of that of the dispersed water and sufficient to stabilize the water dispersion but less than that required to solubilize said water, said quantity of surface-active agent ranging between substantially 0.1% and 10% of the weight of said fabric, said water being present in an amount ranging between substantially 5% and of the'weight of said fabric;

(b) immersing said fabric in said vehicle while agitating same for a period of the order of 5 to 20 minutes at substantially room temperature and effective to result in substantial absorption of water from said vehicle by said fabric; and

(c) removing the fabric from said vehicle; and there'- after drying said fabric.

3. A method as defined in claim 2 wherein said liquor ratio is in step (a) brought to a value on the order of 1:10, said quantity of surface-active agent is substantially 0.5 to 3% and said quantity of water is substantially 5% to 20%.

4. A method as defined in claim 2 wherein said solvent in step (a) is selected from the group which consists of chlorinated hydrocarbons and volatile petroleum fractions.

5. A method as defined in claim 2, further comprising the step of impregnating said fabric with a watersoluble adjuvant by dissolving said adjuvant in said vehicle for transfer to said fabric by the water dispersed in said vehicle.

References Cited UNITED STATES PATENTS 2,061,211 11/1936 Reddish 8142 2,586,105 2/1952 Speakman et al. 2619 FOREIGN PATENTS 460,711 2/ 1937 Great Britain.

ROBERT R. MACKEY, Primary Examiner. 

1. A METHOD OF MILLING A WOOL-CONTAINING FABRIC, COMPRISING THE STEPS OF DISPERSING WATER IN AN ORGANIC VEHICLE CONTAINING A DRY-CLEANING SOLVENT AND PRESENT IN A QUANTITY SUFFICIENT TO PROVIDE A LIQUOR RATIO FROM SUBSTANTIALLY 1:2 TO 1:50 BASED UPON THE WEIGHT OF SOLID FABRIC TO BE TREATED, SAID WATER BEING DISPERSED IN THE PRESENCE OF A QUANTITY OF A SURFACE-ACTIVE AGENT EQUAL TO A SMALL FRACTION OF THAT OF THE DISPERSED WATER AND SUFFICIENT TO 